As a package for packaging contents such as liquid, a viscous substance, powder, a solid, or the like, a package formed by joining films together and sealing peripheral portions of the films has been known.
FIG. 10 is a plan view of a self-standing pouch 900 disclosed in Patent Literature 1. The pouch 900 is produced by inserting a bottom film 903 folded in half, from a fold line side, between a first side-surface film 901 and a second side-surface film 902, and sealing peripheral portions of the films joined together. Further, a spout 904 for taking out contents is attached so as to be sandwiched and sealed between the first side-surface film 901 and the second side-surface film 902. A region excluding the peripheral portions of the films forms a storage part 905 in which the contents are stored. Inside the region where the films are sealed, a non-sealed region 906 is provided over a predetermined length in a height direction. At an upper end of the non-sealed region 906, an air filling portion 908 is formed penetrating through the first side-surface film 901 and/or the second side-surface film, and air is injected into the non-sealed region 906 through the air filling portion 908, thereby forming an air layer 907. By unfolding the bottom film 903 so that the first side-surface film 901 and the second side-surface film 902 form a cylindrical shape at a bottom portion of the pouch 900, the pouch 900 is allowed to stand by itself.
The air layer 907 makes the first side-surface film 901 and the second side-surface film 902 less likely to bend at the air layer 907 and its vicinity. Therefore, when the pouch 900 is made to stand by itself, the overall shape of the pouch 900 is less likely to deform, and thus the self-standing property of the pouch 900 is easily maintained. When the pouch 900 is carried or when the contents are taken out, the air layer 907 serve as a handle. Therefore, a user can easily hold the pouch 900 by grasping the air layer 907.
FIG. 11 is a schematic diagram showing an example of a method for injecting air into the non-sealed region 906. Arrows shown in FIG. 11 indicate the flow of air. Injection of air into the non-sealed region 906 is performed as follows. That is, with an air nozzle 909 being applied to one of the side-surface films and a receiving member 911 for the air nozzle 909 being applied to the other side-surface film, air is blown from an air blowout hole 910 of the air nozzle 909 and injected into the non-sealed region 906 through the air filling portion 908.